Methods and compositions for consolidating particulate matter in a subterranean formation

ABSTRACT

Methods and compositions for consolidating particulate matter in a subterranean formation are provided. In one embodiment, a method of treating a subterranean formation includes coating a curable adhesive composition comprising a silane coupling agent and a polymer having a reactive silicon end group onto proppant material; suspending the coated proppant material in a carrier fluid to form a proppant slurry; introducing the proppant slurry into a subterranean formation; and allowing the curable adhesive composition to at least partially consolidate the proppant material in the subterranean formation.

BACKGROUND

The present invention relates to methods and compositions for treatingsubterranean formations. More particularly, the present inventionrelates to methods and compositions for consolidating particulate matterin a subterranean formation.

Hydrocarbon-producing wells are often stimulated by hydraulic fracturingtreatments. Hydraulic fracturing operations generally involve pumping afracturing fluid into a well bore that penetrates a subterraneanformation at a hydraulic pressure sufficient to create or enhance one ormore cracks, or “fractures,” in the subterranean formation. “Enhancing”one or more fractures in a subterranean formation, as that term is usedherein, is defined to include the extension or enlargement of one ormore natural or previously created fractures in the subterraneanformation. The fracturing fluid may comprise particulates, oftenreferred to as “proppant particulates,” that are deposited in thefractures. The proppant particulates function, inter alia, to preventthe fractures from fully closing upon the release of hydraulic pressure,forming conductive channels through which fluids may flow to the wellbore. After at least one fracture is created and the proppantparticulates are substantially in place, the fracturing fluid may be“broken” (i.e., the viscosity of the fluid is reduced), and thefracturing fluid may be recovered from the formation.

Hydrocarbon-producing wells also may undergo gravel packing treatments,inter alia, to reduce the migration of unconsolidated formationparticulates into the well bore. In gravel-packing treatments, atreatment fluid suspends particulates (commonly referred to as “gravelparticulates”) to be deposited in a desired area in a well bore, e.g.,near unconsolidated or weakly consolidated formation zones, to form agravel pack to enhance sand control. One common type of gravel-packingoperation involves placing a sand control screen in the well bore andpacking the annulus between the screen and the well bore with the gravelparticulates of a specific size designed to prevent the passage offormation sand. The gravel particulates act, inter alia, to prevent theformation particulates from occluding the screen or migrating with theproduced hydrocarbons, and the screen acts, inter alia, to prevent theparticulates from entering the production tubing. Once the gravel packis substantially in place, the viscosity of the treatment fluid may bereduced to allow it to be recovered.

In some situations, fracturing and gravel-packing treatments arecombined into a single treatment (commonly referred to as “frac-pack”operations). In such “frac-pack” operations, the treatments aregenerally completed with a gravel pack screen assembly in place with thehydraulic fracturing treatment being pumped through the annular spacebetween the casing and screen. In this situation, the hydraulicfracturing treatment ends in a screen-out condition, creating an annulargravel pack between the screen and casing. In other cases, thefracturing treatment may be performed prior to installing the screen andplacing a gravel pack.

Occasionally, sand, gravel, proppant, and/or other unconsolidatedparticulates placed in the subterranean formation during a fracturing,gravel packing, or frac-pack operation may migrate out of thesubterranean formation into a well bore and/or may be produced with theoil, gas, water, and/or other fluids produced by the well. The presenceof such particulates, in produced fluids is undesirable in that theparticulates may abrade pumping and other producing equipment and/orreduce the production of desired fluids from the well. Moreover,particulates that have migrated into a well bore (e.g., inside thecasing and/or perforations in a cased hole), among other things, mayclog portions of the well bore, hindering the production of desiredfluids from the well. The term “unconsolidated particulates,” andderivatives thereof, is defined herein to include loose particulates andparticulates bonded with insufficient bond strength to withstand theforces created by the production of fluids through the formation.Unconsolidated particulates may comprise, among other things, sand,gravel, fines and/or proppant particulates in the subterraneanformation.

One method of controlling unconsolidated particulates has been toproduce fluids from the formations at low flow rates. The production ofunconsolidated particulates may still occur, however, due tounintentionally high production rates and/or pressure cycling as mayoccur from repeated shut-ins and start ups of a well. Moreover,producing fluids from the formations at low flow rates may proveeconomically inefficient or unfeasible.

Another technique used to control unconsolidated particulates has beento coat the particulates with a tackifying agent or curable resin priorto their introduction into the subterranean formation and allowing thetackifying agent or resin to consolidate the particulates once insidethe formation. In general, the tackifying agent or resin enhances thegrain-to-grain, or grain-to-formation, contact between particulatesand/or subterranean formation so that the particulates are stabilized,locked in place, or at least partially immobilized such that they areresistant to flowing with produced or injected fluids.

Yet another technique used to control particulates in unconsolidatedformations involves application of a consolidation fluid containingresins or tackifying agents to consolidate particulates into a stable,permeable mass after their placement in the subterranean formation.These consolidation fluids may be preferentially placed in a particularregion of a subterranean formation using isolation tools, such as “packoff” devices, packers, gel plugs, mechanical plugs, bridge plugs, ballsealers, and the like.

SUMMARY

The present invention relates to methods and compositions for treatingsubterranean formation. More particularly, the present invention relatesto methods and compositions for consolidating particulate matter in asubterranean formation.

In one embodiment of the present invention, the invention provides acurable adhesive composition comprising a polymer having a reactivesilicon end group, a catalyst operable to facilitate the curing of thepolymer, a silane coupling agent, and a diluent.

In another embodiment of the present invention, the invention provides amethod of treating a subterranean formation comprising: coating acurable adhesive composition comprising a silane coupling agent and apolymer having a reactive silicon end group onto proppant material;suspending the coated proppant material in a carrier fluid to form anproppant slurry; introducing the proppant slurry into a subterraneanformation; and allowing the curable adhesive composition to at leastpartially consolidate the proppant material in the subterraneanformation.

In yet another embodiment of the present invention, the inventionprovides a method of treating a subterranean formation comprising:introducing a pre-flush fluid into a subterrean formation; introducing acurable adhesive composition comprising a silane coupling agent and apolymer having a reactive silicon end group into the subterraneanformation subsequent to the pre-flush fluid; introducing an aqueouspost-fluid fluid into the subterranean formation subsequent to thecurable adhesive composition; and allowing the curable adhesivecomposition to at least partially consolidate particulate matter withinthe subterranean formation.

The features and advantages of the present invention will be readilyapparent to those skilled in the art. While numerous changes may be madeby those skilled in the art, such changes are within the spirit of theinvention.

DESCRIPTION OF PREFERRED EMBODIMENTS

The present invention relates to methods and compositions for treatingsubterranean formations. More particularly, the present inventionrelates to methods and compositions for consolidating particulate matterwithin a subterranean formation.

Generally, the methods and compositions of the present invention may beused for primary treatments, remedial treatments, and/or proactivetreatments of a subterranean formation. As used herein, “primarytreatment” refers to any treatment in which a curable adhesivecomposition is coated onto particulate matter that is then placed into asubterranean formation, for example, in a fracturing, gravel-packing, orfrac-pack treatment; “remedial treatment” refers to any treatment inwhich a curable adhesive composition is coated onto particulate matterthat has been previously placed in a subterranean formation, forexample, in a fracturing, gravel-packing, or frac-pack treatment; and“proactive treatment” refers to any treatment in which a curableadhesive composition is coated onto the surface of a subterraneanformation prior to a treatment, such as a fracturing, gravel-packing, orfrac-pack treatment, or that might introduce or produce unconsolidatedparticulates in the subterranean formation, for example, as a pre-pad tothe fracturing treatment or in any diagnostic pumping stage performedprior to a fracturing, gravel packing, or acidizing procedure.Generally, whether a particular method of the present invention is“primary,” “remedial,” or “proactive” is determined relative to thetiming of a fracturing, gravel-packing, or frac-pack treatment. Usingthe compositions and methods of the present invention, particulateswithin the formation may be consolidated into a cohesive, consolidated,yet permeable pack to minimize or reduce their production withproduction fluids, helping the particulates to better withstand dragforces caused by high production and/or injection flow rates.

One of the advantages of some embodiments of the present invention, manyof which are not discussed herein, is that the compositions and methodsof the present invention may be more economical than previous treatmentsemploying epoxy-based or furan-based resins. The curable adhesivecompositions may also pose fewer environmental or safety concerns thanepoxy-based, furan-based, or other rubber-based adhesive compositions,which often contain solvents that are toxic and/or flammable. Thecurable adhesive compositions may also yield cohesive, yet relativelyelastic, packs that may be able to withstand additional stresses.

Generally, the curable adhesive compositions of the present inventioncomprise a silane coupling agent and a polymer having a reactive siliconend group. In some embodiments, the curable adhesive composition mayalso include a catalyst operable to facilitate the curing of thepolymer, a diluent, a dehydrating agent, and/or a filler material.

Generally, any suitable polymer that can be prepared with reactivesilicon end groups may be used in accordance with particular embodimentsof the present invention. Examples of suitable polymers include, but arenot limited to, polyalkyls, such as polyethers, polyalkanes,polyalkenes, and polyalkynes; substituted alkyl monomers, such asstyrene; acrylics; and combinations thereof. Examples of suitablereactive silicon end groups include, but are not limited to,triethoxysilanes, methyldiethoxysilanes, trisilanols, alkoxysilanes,substituted silanes, multi-silanols, and combinations thereof. Onesuitable polymer having a reactive silicon end group that may be used inparticular embodiments of the present invention is a silane-modifiedpoly(propylene oxide) oligomer.

Generally, the polymer having a reactive silicon end group may bepresent in the curable adhesive composition in an amount from about 10%to about 80% by weight of the composition. In particular embodiments ofthe present invention, the curable adhesive compositions used forprimary treatments may generally contain a greater percentage of polymerhaving a reactive silicon end group than those compositions used forremedial or proactive treatments. For example, in some embodiments usedfor primary treatment, the polymer having a reactive silicon end groupmay be present in the curable adhesive composition in an amount fromabout 30% to about 80% by weight of composition. In particular primarytreatment embodiments, the polymer having a reactive silicon end groupmay be present in the curable adhesive composition in an amount fromabout 40% to about 70% by weight of the composition. In other primarytreatment embodiments, the polymer having a reactive silicon end groupmay comprise at least about 60% by weight of curable adhesivecomposition. In contrast, in some embodiments used for remedial and/orproactive treatments, the polymer having a reactive silicon end groupmay be present in the curable adhesive composition in an amount fromabout 0.1% to about 30% by weight of the composition, and preferably inan amount from about 1% to about 10% by weight of the composition. Withthe benefit of this disclosure, it should be within the ability of oneof ordinary skill in the art to select an appropriate amount of polymerhaving a reactive silicon end group for use in a particular application.

The curable adhesive composition may also comprise a silane couplingagent, which facilitates the adhesion of the curable adhesivecomposition to the particulates. Generally, any suitable silane couplingagent may be used in accordance with particular embodiments of thepresent invention. Examples of suitable silane coupling agents include,but are not limited to, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane;3-glycidoxypropyltrimethoxysilane; gamma-aminopropyltriethoxysilane;N-beta-(aminoethyl)-gamma-aminopropyltrimethoxysilane;aminoethyl-N-beta-(aminoethyl)-gamma-aminopropyl-trimethoxysilane;gamma-ureidopropyl-triethoxysilane;beta-(3,4-epoxy-cyclohexyl)-ethyltrimethoxysilane;gamma-glycidoxypropyltrimethoxysilane; vinyltrichlorosilane;vinyltris(beta-methoxyethoxy)silane; vinyltriethoxysilane;vinyltrimethoxysilane; 3-methacryloxypropyltrimethoxysilane;r-glycidoxypropyltrimethoxysilane;r-glycidoxypropylmethyldiethoxysilane;N-beta-(aminoethyl)-r-aminopropyl-trimethoxysilane;N-beta-(aminoethyl)-r-aminopropylmethyldimethoxysilane;3-aminopropyl-triethoxysilane; N-phenyl-r-aminopropyltrimethoxysilane;r-mercaptopropyltrimethoxysilane; r-chloropropyltrimethoxysilane;r-methacryloxypropyltrimethoxysilane; r-aminopropyltriethoxysilane;N-[3-(trimethoxysilyl)propyl]-ethylenediamine; substituted silanes whereone or more of the substitutions contains a different functional group;and combinations thereof. In some embodiments, the silane coupling agentmay be present in the curable adhesive composition in an amount fromabout 0.1% to about 5% by weight of the composition, and preferably inan amount from about 0.5% to about 3% by weight of the composition.

In some embodiments, the curable adhesive composition of the presentinvention may also comprise an optional catalyst to facilitate thecuring of the adhesive composition. Generally, any suitable catalyst maybe used in the curable adhesive compositions of the present invention.Examples of suitable catalysts include, but are not limited to, tertiaryamine catalysts, titanium chelate catalysts, tin catalysts, leadcatalysts, bismuth catalysts, and combinations thereof. One suitablecatalyst that may be used in particular embodiments of the presentinvention is dibutylbis(2,4-pentanedionate-O,O′)—, (OC-6-11). In someembodiments, the catalyst may be present in the curable adhesivecomposition in an amount from about 0.1% to about 5% by weight of thecomposition, and preferably in an amount from about 1% to about 3% byweight of the composition.

In some embodiments, the curable adhesive composition of the presentinvention may also include an optional diluent. In particularembodiments, the presence of a diluent helps reduce the viscosity of thecurable adhesive composition to improve its flowability and enhance itscoating effectiveness onto particulate matter. Generally, the curableadhesive composition may have a viscosity less than about 1,500 cP. Insome embodiments, such as those used for primary treatments, the curableadhesive composition may have a viscosity in the range from about 250 cPto about 1,500 cP, and, preferably, from about 450 cP to about 800 cP.In other embodiments, such as those used for remedial or proactivetreatments, the curable adhesive composition may have a viscosity lessthan about 50 cP, and, preferably, less than about 10 cP. Examples ofsuitable diluents include, but are not limited to, hydrocarbons, such asdiesel and kerosene; polyglycols, such as polypropylene; mineral oils,such as white mineral oil and petroleum oil; vegetable oils, such ascastor oil, corn oil, and peanut oil; tall oil fatty acids;monofunctional polyether polymers; phthalate plasticizers, such as butylbenzyl phthalate and diisodecyl phthalate; and combinations thereof.Generally, the diluent may be present in the curable adhesivecomposition in an amount from about 20% to about 70% by weight of thecomposition. In some embodiments, such as those for use in primarytreatments, the diluent may be present in the curable adhesivecomposition in an amount from about 30% to about 60% by weight of thecomposition. In other embodiments, such as those for use in remedial orproactive treatments, the diluent may be present in the curable adhesivecomposition in an amount from about 70% to about 99% by weight of thecomposition, and preferably in an amount from about 85% to about 95% byweight of the composition.

In some embodiments, the curable adhesive composition may also includean optional dehydrating agent. Examples of suitable dehydrating agentsinclude, but are not limited to, vinyl trimethoxysilane, any vinylalkoxysilane, inorganic zeolites, organic zeolites, and combinationsthereof. In some embodiments, the dehydrating agent may be present inthe curable adhesive composition in an amount from about 0.1% to about10% by weight of the composition, and preferably in an amount from about0.5% to about 3% by weight of the composition.

Particular embodiments of the curable adhesive composition may alsoinclude an optional filler material to, among other things, helpstrengthen the adhesive composition. Examples of suitable fillermaterials include, but are not limited to, zinc oxide, reinforcingcarbon black, non-reinforcing carbon black, semi-reinforcing carbonblack, white carbon, expanded graphite powder, powdery graphite,crystalline silica, ground nut shells, silicates, chalk, calciumcarbonate (including limestone), talc, mica, alumina, aluminumhydroxide, zirconia, titanium dioxide, wollastonite, feldspar, aluminumsilicates, solid ceramic microspheres, hollow ceramic microspheres,hollow ceramic spheres, hollow plastic spheres, metal powders, metalmicrobeads, wood flour, dolomite, organic pigments, inorganic pigments,fumed amorphous silica (including hydrophilic and hydrophobic types),glass microbeads, glass fibers, clear polymer fibers, clear polymermicrobeads, clear polymer powders, and combinations thereof. In someembodiments, the filler material may be present in the curable adhesivecomposition in an amount from about 1% to about 30% by weight of thecomposition, and preferably in an amount from about 2% to about 10% byweight of the composition.

In particular embodiments, the curable adhesive compositions of thepresent invention may be used in a primary method to coat particulatematter, such as proppant, that is then placed in the subterraneanformation using a well treatment fluid, such as a fracturing fluid orgravel pack fluid. One example of such a method comprises coating acurable adhesive composition comprising a silane coupling agent and apolymer having a reactive silicon end group onto proppant material;suspending the coated proppant material in a carrier fluid to form aproppant slurry; introducing the proppant slurry into a subterraneanformation; and allowing the curable adhesive composition to at leastpartially consolidate the proppant material once it is place into thesubterranean formation. Another example of such a method comprises:providing a gravel pack fluid that comprises gravel coated with acurable adhesive composition, the curable adhesive compositioncomprising a silane coupling agent and a polymer having a reactivesilicon end group; contacting a portion of the subterranean formationwith the gravel pack fluid so as to place a gravel pack in or near aportion of the subterranean formation; and allowing the curable adhesivecomposition to consolidate the gravel once it is placed within thesubterranean formation. The fracturing and/or gravel pack fluids inthese primary embodiments may comprise any suitable component usuallyfound in fracturing fluids in view of the characteristics of theformation including, but not limited to, an aqueous base fluid, proppantparticulates, gelling agents, surfactants, breakers, buffers, a gasphase (if the fracturing fluid is foamed or commingled), couplingagents, and the like. One of ordinary skill in the art with the benefitof this disclosure will recognize the appropriate components for use infracturing or gravel pack fluid for use in conjunction with a curableadhesive composition of the present invention for a given application.

In particular embodiments, the curable adhesive compositions of thepresent invention may be coated on particulates to be used in afracturing or gravel packing process like those described above. As usedherein, the term “coated” implies no particular degree of coverage ormechanism by which the consolidating agent becomes incorporated with theparticulates. Moreover, as used herein, “coating” includes, but is notlimited to, simple coating, adhesion, and impregnation. In particularembodiments of the present invention, this coating of the curableadhesive composition onto some or all of the particulates, as well asany mixing of the coated particulates with a fracturing or treatmentfluid, may be performed “on-the-fly,” in which a flowing stream iscontinuously introduced into another flowing stream so that the streamsare combined and mixed while continuing to flow as a single stream. Asis well understood by those skilled in the art, such mixing may also beaccomplished by batch mixing or partial batch mixing. In particularembodiments, the curable adhesive composition may be coated onto dryparticulates while the particulates are conveyed by a conveying and/ormixing device, such as a sandscrew or auger, into the fracturing orgravel packing fluid.

In particular embodiments of the present invention, the coatedparticulates may be introduced as part of a fracturing or gravel packingprocess at any point during a fracturing or gravel packing treatment.For example, in particular embodiments, the coated particulates may beintroduced towards the end of a fracturing or gravel packing treatmentso that the maximum economic benefit can be obtained. One of ordinaryskill in the art will readily understand the economic value of placingthe adhesive-coated particulates at only certain points during theplacement of the particulates.

One of ordinary skill in the art will also appreciate the appropriateamount of curable adhesive composition to coat onto the particulate fora given application. In some embodiments, the amount of curable adhesivecomposition coated onto the particulates may be in the range from about0.1% to about 20% by weight of the particulate. In particularembodiments, the amount of curable adhesive composition coated onto theparticulates may be in the range of from about 1% to about 5% by weightof the particulate.

A wide variety of particulate materials may be used in accordance withthe present invention, including, but not limited to, sand, bauxite,ceramic materials, glass materials, polymer materials,tetrafluoroethylene materials, nut shells, ground or crushed nut shells,seed shells, ground or crushed seed shells, fruit pit pieces, ground orcrushed fruit pits, processed wood, composite particulates prepared froma binder with filler particulate including silica, alumina, fumedcarbon, carbon black, graphite, mica, titanium dioxide, meta-silicate,calcium silicate, kaolin, talc, zirconia, boron, fly ash, hollow glassmicrospheres, solid glass, and mixtures thereof. The particulatematerial used may have a particle size in the range from about 2 toabout 400 mesh, U.S. Sieve Series. In particular embodiments, theparticulate material may be graded sand having a particle size in therange from about 10 to about 70 mesh, U.S. Sieve Series. Preferred sandparticle size distribution ranges may be one or more of 10-20 mesh,20-40 mesh, 40-60 mesh, or 50-70 mesh, depending on the particle sizeand distribution of the formation particulates to be screened out by theparticulate materials. Other particulates that may be suitable for usein subterranean applications also may be useful.

In particular embodiments, the curable adhesive compositions of thepresent invention may also be used to remediate proppant and otherparticulate matter that has previously been placed in a subterraneanformation. For example, in some embodiments of the present invention,after a fracturing treatment or a gravel pack treatment has beenperformed, the curable adhesive compositions of the present inventionmay be introduced into an unconsolidated zone of a subterraneanformation to stabilize particulates within the zone. The curableadhesive compositions may disperse any loose fines within a proppantpack in a fracture, move any fines away from the fracture (or near thewell bore), stabilize gravel particulates around a screen, stabilize ascreen failure, and/or lock the fines in the formation. In anotherremedial embodiment, the curable adhesive compositions of the presentinvention may be introduced into a subterranean formation that isproducing unconsolidated particulate material as a result of, interalia, depletion, water breakthrough, etc. The curable adhesivecomposition may stabilize and/or strengthen the weakly consolidated orunconsolidated particulates in the formation and thereby reduce theirundesirable production. For such remedial treatments, the curableadhesive composition is generally more dilute than when used for primarytreatments. For example, in particular embodiments used for remedialtreatments, the curable adhesive may comprise from about 0.1% to about30% by weight polymers having reactive silicon end groups, compared toabout 30% to about 80% by weight polymers having reactive silicon endgroups in a primary treatment.

The amount of curable adhesive composition to be used for a givenremedial treatment may be determined based on the number of perforationsin the well bore and/or the length of the perforated interval to betreated. For example, in some embodiments, the curable adhesivecomposition used to treat proppant previously placed in fractures isgenerally used in an amount from about 1.25 to about 5 gallons per footof the perforated interval to be treated. In some embodiments, thecurable adhesive composition is used in an amount from about 2.5 toabout 5 gallons per foot of the perforated interval to be treated. Thisamount assumes that each one-foot interval includes approximately 2fractures, and that each fracture is to be treated to a depth ofapproximately 10 feet into the fracture. Depending on the number offractures to be treated and the depth to which it is desired to treatthe fractures, more or less curable adhesive composition may be used.With the benefit of this disclosure, one of ordinary skill in the artshould be able to determine a suitable amount of curable adhesivecomposition to use to remedially treat a particular subterraneanformation.

In some embodiments, the curable adhesive compositions of the presentinvention may also be used in a proactive treatment. Such treatments maybe best suited for wells that have not been fractured or gravel packed.These methods may be used as a pre-treatment before a fracturingtreatment or at the early stage of a fracturing treatment (includingdiagnostic pumping) as a pre-pad treatment. In some proactiveembodiments of the present invention, the curable adhesive compositionof the present invention may be introduced into an unconsolidated zoneof a subterranean formation to stabilize particulates within the zone.In some embodiments, the proactive methods of the present inventioncomprise placing the curable adhesive composition before or as part of apre-pad of a fracturing treatment into a subterranean formation. Similarto remedial treatments, for such proactive treatments, the curableadhesive composition is generally more dilute than when used for primarytreatments. For example, in particular embodiments used for proactivetreatments, the curable adhesive may comprise from about 0.1% to about30% by weight polymers having reactive silicon end groups, compared toabout 30% to about 80% by weight polymers having reactive silicon endgroups in a primary treatment. In particular embodiments, the amount ofcurable adhesive composition used to proactively treat a subterraneanformation may range from about 10 gallons per foot of formation intervalto be treated to about 200 gallons per foot of formation interval to betreated. Preferably, the curable adhesive composition used toproactively treat a subterranean formation may range from about 30gallons per foot of formation interval to be treated to about 100gallons per foot of formation interval to be treated. With the benefitof this disclosure, one of ordinary skill in the art should be able todetermine a suitable amount of curable adhesive composition to use toproactively treat a particular subterranean formation.

In some embodiments, subsequent to placing the curable adhesivecomposition in the formation, the subterranean formation may befractured. This fracturing step may include the introduction of aplurality of particulates into the formation. In some embodiments, atleast a portion of the particulates may be coated with a consolidatingagent, such as the curable adhesive compositions of the presentinvention. In some embodiments, the coated particulates may beintroduced into the fluid at the end of the fracturing treatment. Insome embodiments, at least a plurality of the particulates may be of alarger size, such that the fracture has a higher conductivity. Forexample, the size of at least a plurality of the particulates may have aweight mean particle size (“d50”) of about 20 times to about 50 timesthe d50 of the formation particulates.

In some embodiments, the curable adhesive compositions of the presentinvention may be used in a supported open-hole well bore. In supportedopen-hole well bores, a slotted liner or screen, for example, may beused to provide mechanical support and/or to allow the bore hole toconform and/or comply to the liner in very weak formation layers. Inaddition, in some supported open-hole well bores, zonal isolationpackers may also be used. It may be desirable in certain embodiments touse the curable adhesive composition of the present invention in asupported open-hole well bore. One potential advantage of using thecurable adhesive compositions of the present invention in a supportedopen hole well bore is that the formation around the well bore may bestabilized, thus mitigating any fines movement or long term plugging,such that the placement of a gravel pack may no longer be necessary.

In some remedial and proactive treatments, the application of thecurable adhesive composition may be preceded by the application of apre-flush fluid. Such a pre-flush fluid may help to remove debris fromthe flow path, displace reservoir fluids, and/or precondition thesurface of the particulate matter for accepting the adhesive coating inthe curable adhesive composition. Examples of suitable pre-flush fluidsinclude aqueous and solvent-based fluids. In some embodiments, aqueouspre-flush fluid may comprise fresh water, saltwater (e.g., watercontaining one or more salts dissolved therein), brine (e.g., saturatedsaltwater), seawater, or combinations thereof, and may be from anysource, provided that they do not contain components that mightadversely affect the stability and/or performance of the consolidationfluids of the present invention. In other embodiments, solvent-basedfluids may comprise a glycol ether solvent, such as diethylene glycolmonomethyl ether, diethylene glycol dimethyl ether, ethylene glycolmonobutyl ether, or dipropylene glycol monomethyl ether.

In some remedial or proactive treatments, application of the curableadhesive composition may be followed by the application of a post-flushfluid. Such a post-flush fluid may help remove excess curable adhesivecomposition from the pore spaces between the particulates and/or reducepermeability loss in the consolidated pack. Examples of suitablepost-fluid fluids include, but are not limited to, gases, such air andnitrogen, foamed aqueous fluids, such as brine, and hydrocarbon fluids,such as diesel and kerosene. In particular embodiments where a gaseouspost-flush fluid is applied, the fluid may be applied in an amount fromabout 25 to about 200 cubic feet per foot of perforated interval to betreated depending on the temperature and pressure at the interval ofinterest. In other embodiments, where a foamed post-flush fluid isapplied, the fluid may be applied in an amount from about one to twotimes the volume of the curable adhesive composition applied. With thebenefit of this disclosure, one of ordinary skill in the art should beable to determine an appropriate amount of post-flush fluid to apply ina given remedial or proactive treatment.

In general, when used in a remedial or proactive treatment, the curableadhesive compositions, pre-flush fluids, and/or post-flush fluids of thepresent invention may be bullheaded into the well, i.e., pumped into thewell bore without the use of isolation tools or barrier devices underthe assumption that the fluid will be placed into a target area, orplaced using coiled tubing or jointed pipe to treat intervals ofinterest. In some embodiments, mechanical isolation devices and packersmay be used in combination with coiled tubing or jointed pipe to dividethe well bore into shorter intervals. A pressure pulsing tool orrotating jetting tool may also be coupled with the coiled tubing orjointed pipe to enhance the placement of the fluid into an interval. Forexample, a pressure pulsing tool based on fluid-oscillation may be usedto create pulsating pressure waves within the well bore and formationfluids to enhance the penetration of the treatment fluids further intothe fractures and formations.

After application of the curable adhesive composition and any pre-flushor post-flush fluids, the well may be shut in for a period of time toallow the curable adhesive to cure. The amount of time necessary for theadhesive to cure sufficiently may depend on temperature and/or thecomposition of the adhesive. In some embodiments, positive pressure maybe maintained in the well bore during shut in to prevent or reduce fluidswabbing into the well bore from the formations surrounding the wellbore. Similarly, positive pressure may be maintained in the well boreduring the removal of the equipment used to place the curable adhesivecomposition, pre-flush fluid, and/or post-flush fluid to similarlyprevent or reduce fluid swabbing.

As stated above, the remedial and/or proactive treatments of the presentinvention may be employed in any subterranean treatment whereunconsolidated particulates may reside in the formation. Theseunconsolidated particulates may comprise, among other things, sand,gravel, fines and/or proppant particulates within the open space of oneor more fractures in the subterranean formation (e.g., unconsolidatedparticulates that form a proppant pack or gravel pack within theformation). Using the curable adhesive compositions and methods of thepresent invention, the unconsolidated particulates within the formationmay be remedially or proactively treated to consolidate the particulatesinto a cohesive, consolidated, yet permeable pack and minimize or reducetheir production with production fluids. For example, in someembodiments, the curable adhesive composition, pre-flush fluid, and/orpost-fluid fluid may be applied to remedially treat a gravel pack orfrac-packs that has failed due to screen damage (often caused by screenerosion) to reduce the production of gravel, proppant, or formation sandwith the production fluid. In one embodiment, the present inventionprovides a method of treating a subterranean formation comprisingintroducing a pre-flush fluid into a subterranean formation; introducinga curable adhesive composition comprising a silane coupling agent and apolymer having a reactive silicon end group into the subterraneanformation subsequent to the pre-flush fluid; introducing an aqueouspost-fluid fluid into the subterranean formation subsequent to thecurable adhesive composition; and allowing the curable adhesivecomposition to at least partially consolidate particulate matter withinthe subterranean formation.

To facilitate a better understanding of the present invention, thefollowing examples of specific embodiments are given. In no way shouldthe following examples be read to limit or define the entire scope ofthe invention.

EXAMPLE 1

A curable adhesive composition was prepared by mixing 35 ccsilane-modified poly(propylene oxide) oligomer; 0.5 ccdibutylbis(2,4-pentanedionate-O,O′)—, (OC-6-11); 1 ccN-[3-(trimethoxysilyl)propyl]-ethylenediamine; 15 cc diesel; and 0.5 ccvinyltrimethoxysilane into a homogeneous solution. Six cc of thiscurable adhesive composition was then dry coated onto 200 g of20/40-mesh Brady sandy (i.e., 3% v/w) using a spatula. The coated sandwas then suspended and mixed in 300 cc of 3% KCl brine to form a coatedsand slurry, in which the coated sand became tacky. The brine wasdecanted, and the coated sand was packed into a 5 inch-long brasscylinder having an inner diameter of 1⅜ inches. The top and bottom ofthe brass chamber were capped to form a sealed system, which was thenplaced in an oven and cured at 200° F. for 20 hours.

After curing, a firm sand pack was extruded from the brass chamber andcut into sized cores approximately 1⅜ inches in diameter and 2 inches inlength for unconfined compressive strength (“UCS”) measurements. It wasobserved that the cores were very elastic. The cores never crumbled orcrushed even after their original lengths were reduced more than 25%.Once the stress load was removed, the cores returned to their originallengths. This process was repeated at least three times. The highest UCSvalue obtained was 90 psi.

EXAMPLE 2

A curable adhesive composition was prepared by mixing 20 ccsilane-modified poly(propylene oxide) oligomer; 1 ccdibutylbis(2,4-pentanedionate-O,O′)—, (OC-6-11); 2 ccN-[3-(trimethoxysilyl)propyl]-ethylenediamine; 80 cc diesel; and 1 ccvinyltrimethoxysilane into a homogeneous solution.

A sand pack of 20/40-mesh Brady sand was dry packed into a brass 5inch-ling brass cylinder having an inner diameter of 1⅜ inches using a60-mesh wire mesh screen placed at the bottom of the cylinder to holdthe sand in place. The resultant sand column was then saturated withdiesel by flushing 3 pore volumes (150 cc) of diesel through the column.Next, a pore volume (50 cc) of the curable adhesive composition wasflushed through the sand column. A post-flush of 2 pore volumes (100 cc)of 3% KCl brine was then flushed through the sand column. The top andbottom of the brass chamber were capped to form a sealed system, whichwas then placed in an oven and cured at 200° F. for 20 hours.

After curing, a firm sand pack was extruded from the brass chamber andcut into sized cores approximately 1⅜ inches in diameter and 2 incheslong for UCS measurements. It was observed that the cores were veryelastic. The cores never crumbled or crushed even after their originallengths were reduced more than 25%. Once the stress load was removed,the cores returned to their original lengths. The highest UCS valueobtained was 25 psi.

EXAMPLE 3

A curable adhesive composition was prepared by mixing 15 ccsilane-modified poly(propylene oxide) oligomer; 1 ccdibutylbis(2,4-pentanedionate-O,O′)—, (OC-6-11); 2 ccN-[3-(trimethoxysilyl)propyl]-ethylenediamine; 85 cc diesel; and 1 ccvinyltrimethoxysilane into a homogeneous solution.

A sand pack of 20/40-mesh Brady sand was dry packed into a 5 inch-longbrass cylinder having an inner diameter of 1⅜ inches using a 60-meshwire mesh screen placed at the bottom of the chamber to hold the sand inplace. The resultant sand column was then saturated with diesel byflushing 3 pore volumes (150 cc) of diesel through the column. Next, apore volume (50 cc) of the curable adhesive composition was flushedthrough the sand column. A post-flush of 2 pore volumes (100 cc) of 3%KCl brine was then flushed through the sand column. The top and bottomof the brass cylinder were capped to form a sealed system, which wasthen placed in an oven and cured at 200° F. for 20 hours.

After curing, a firm sand pack was extruded from the brass cylinder andcut into sized cores approximately 1⅜ inches in diameter and 2 incheslong for UCS measurements. It was observed that the cores were veryelastic. The cores never crumbled or crushed even after their originallengths were reduced more than 25%. Once the stress load was removed,the cores returned to their original lengths. The highest UCS valueobtained was 8 psi.

Therefore, the present invention is well adapted to attain the ends andadvantages mentioned as well as those that are inherent therein. Theparticular embodiments disclosed above are illustrative only, as thepresent invention may be modified and practiced in different butequivalent manners apparent to those skilled in the art having thebenefit of the teachings herein. While numerous changes may be made bythose skilled in the art, such changes are encompassed within the spiritof this invention as defined by the appended claims. Furthermore, nolimitations are intended to the details of construction or design hereinshown, other than as described in the claims below. It is thereforeevident that the particular illustrative embodiments disclosed above maybe altered or modified and all such variations are considered within thescope and spirit of the present invention. In particular, every range ofvalues (e.g., “from about a to about b,” or, equivalently, “fromapproximately a to b,” or, equivalently, “from approximately a-b”)disclosed herein is to be understood as referring to the power set (theset of all subsets) of the respective range of values. The terms in theclaims have their plain, ordinary meaning unless otherwise explicitlyand clearly defined by the patentee.

1. A method of treating a subterranean formation, the method comprising:coating a curable adhesive composition onto a proppant material, therebyforming a coated proppant material; wherein the curable adhesivecomposition comprises a silane coupling agent and a polymer, the polymerhaving a reactive silicon end group; suspending the coated proppantmaterial in a carrier fluid to form a proppant slurry; introducing theproppant slurry into a subterranean formation; and allowing the curableadhesive composition to at least partially consolidate the proppantmaterial in the subterranean formation.
 2. The method of claim 1,wherein the polymer comprises a component selected from the groupconsisting of polyalkyl oxides, polyethers, polyalkanes, polyalkenes,polyalkynes, substituted alkyl monomers, styrenes, acrylics, andcombinations thereof.
 3. The method of claim 1, wherein the reactivesilicon end group comprises a component selected from the groupconsisting of triethoxysilanes, methyldiethoxysilanes, trisilanols,alkoxysilanes, substituted silanes, and multi-silanols.
 4. The method ofclaim 1, wherein the silane coupling agent comprises a componentselected from the group consisting ofN-2-(aminoethyl)-3-aminopropyltrimethoxysilane;3-glycidoxypropyltrimethoxysilane; gamma-aminopropyltriethoxysilane;N-beta-(aminoethyl)-gamma-aminopropyltrimethoxysilane;aminoethyl-N-beta-(aminoethyl)-gamma-aminopropyl-trimethoxysilane;gamma-ureidopropyl-triethoxysilane;beta-(3,4-epoxy-cyclohexyl)-ethyltrimethoxysilane;gamma-glycidoxypropyltrimethoxysilane;vinyltris(beta-methoxyethoxy)silane; vinyltriethoxysilane;vinyltrimethoxysilane; 3-methacryloxypropyltrimethoxysilane;beta-(3,4-epoxycyclohexyl)-ethyltrimethoxysilane;r-glycidoxypropyltrimethoxysilane;r-glycidoxypropylmethyldiethoxysilane;N-beta-(aminoethyl)-r-aminopropyl-trimethoxysilane;N-beta-(aminoethyl)-r-aminopropylmethyldimethoxysilane;3-aminopropyl-triethoxysilane; N-phenyl-r-aminopropyltrimethoxysilane;r-mercaptopropyltrimethoxysilane; r-chloropropyltrimethoxysilane;vinyltrichlorosilane; r-methacryloxypropyltrimethoxysilane;r-aminopropyltriethoxysilane;N-[3-(trimethoxysilyl)propyl]-ethylenediamine; and substituted silaneswhere one or more of the substitutions contains a different functionalgroup.
 5. The method of claim 1, wherein the curable adhesivecomposition further comprises a catalyst operable to cure the polymer,the catalyst comprising a component selected from the group consistingof tertiary amine catalysts, titanium chelate catalysts, tin catalysts,lead catalysts, and bismuth catalysts.
 6. The method of claim 1, whereinthe curable adhesive composition further comprises a diluent comprisinga component selected from the group consisting of hydrocarbons, diesel,kerosene, polyglycols, polypropylene glycol, mineral oils, white mineraloil, petroleum oil, vegetable oil, castor oil, corn oil, peanut oil,tall oil fatty acids, monofunctional polyether polymers, phthalateplasticizers, butyl benzyl phthalate, and diisodecyl phthalate.
 7. Themethod of claim 1, wherein the curable adhesive composition furthercomprises a dehydrating agent comprising a component selected from thegroup consisting of vinyl trimethoxysilane, vinyl alkoxysilane,inorganic zeolites, and organic zeolites.
 8. The method of claim 1,wherein the polymer comprises about 10% to about 80% by weight of thecurable adhesive composition.
 9. The method of claim 1, wherein thepolymer comprises about 0.1% to about 30% by weight of the curableadhesive composition.
 10. The method of claim 1, wherein the curableadhesive composition comprises about 0.1% to about 20% by weight of thecoated proppant material.
 11. The method of claim 1, wherein the curableadhesive composition further comprises a filler material comprising acomponent selected from the group consisting of zinc oxide, reinforcingcarbon black, non-reinforcing carbon black, semi-reinforcing carbonblack, white carbon, expanded graphite powder, powdery graphite,crystalline silica, ground nut shells, silicates, chalk, calciumcarbonate, limestone, talc, mica, alumina, aluminum hydroxide, zirconia,titanium dioxide, wollastonite, feldspar, aluminum silicates, solidceramic microspheres, hollow ceramic microspheres, hollow plasticspheres, metal powders, metal microbeads, wood flour, dolomite, organicpigments, inorganic pigments, fumed amorphous silica, hydrophilic fumedamorphous silica, hydrophobic fumed amorphous silica, glass microbeads,clear polymer powders, and combinations thereof.
 12. A method oftreating a subterranean formation, the method comprising: providingcoated particulates comprising a curable adhesive composition; whereinthe curable adhesive composition comprises a silane coupling agent and apolymer, the polymer having a reactive silicon end group; introducingthe coated particulates into a subterranean formation; and allowing thecurable adhesive composition to at least partially cure in thesubterranean formation.
 13. The method of claim 12, further comprising:performing a fracturing operation or a gravel packing operation in thesubterranean formation.
 14. The method of claim 12, wherein the polymercomprises a component selected from the group consisting of polyalkyloxides, polyethers, polyalkanes, polyalkenes, polyalkynes, substitutedalkyl monomers, styrenes, acrylics, and combinations thereof.
 15. Themethod of claim 12, wherein the reactive silicon end group comprises acomponent selected from the group consisting of triethoxysilanes,methyldiethoxysilanes, trisilanols, alkoxysilanes, substituted silanes,and multi-silanols.
 16. The method of claim 12, wherein the silanecoupling agent comprises a component selected from the group consistingof N-2-(aminoethyl)-3-aminopropyltrimethoxysilane;3-glycidoxypropyltrimethoxysilane; gamma-aminopropyltriethoxysilane;N-beta-(aminoethyl)-gamma-aminopropyltrimethoxysilane;aminoethyl-N-beta-(aminoethyl)-gamma-aminopropyl-trimethoxysilane;gamma-ureidopropyl-triethoxysilane;beta-(3,4-epoxy-cyclohexyl)-ethyltrimethoxysilane;gamma-glycidoxypropyltrimethoxysilane;vinyltris(beta-methoxyethoxy)silane; vinyltriethoxysilane;vinyltrimethoxysilane; 3-methacryloxypropyltrimethoxysilane;beta-(3,4-epoxycyclohexyl)-ethyltrimethoxysilane;r-glycidoxypropyltrimethoxysilane;r-glycidoxypropylmethyldiethoxysilane;N-beta-(aminoethyl)-r-aminopropyl-trimethoxysilane;N-beta-(aminoethyl)-r-aminopropylmethyldimethoxysilane;3-aminopropyl-triethoxysilane; N-phenyl-r-aminopropyltrimethoxysilane;r-mercaptopropyltrimethoxysilane; r-chloropropyltrimethoxysilane;vinyltrichlorosilane; r-methacryloxypropyltrimethoxysilane;r-aminopropyltriethoxysilane;N-[3-(trimethoxysilyl)propyl]-ethylenediamine; and substituted silaneswhere one or more of the substitutions contains a different functionalgroup.
 17. The method of claim 12, wherein the curable adhesivecomposition further comprises a catalyst operable to cure the polymer,the catalyst comprising a component selected from the group consistingof tertiary amine catalysts, titanium chelate catalysts, tin catalysts,lead catalysts, and bismuth catalysts.
 18. The method of claim 12,wherein the curable adhesive composition further comprises a diluentcomprising a component selected from the group consisting ofhydrocarbons, diesel, kerosene, polyglycols, polypropylene glycol,mineral oils, white mineral oil, petroleum oil, vegetable oil, castoroil, corn oil, peanut oil, tall oil fatty acids, monofunctionalpolyether polymers, phthalate plasticizers, butyl benzyl phthalate, anddiisodecyl phthalate.
 19. The method of claim 12, wherein the curableadhesive composition further comprises a dehydrating agent comprising acomponent selected from the group consisting of vinyl trimethoxysilane,vinyl alkoxysilane, inorganic zeolites, and organic zeolites.
 20. Themethod of claim 12, wherein the polymer comprises about 10% to about 80%by weight of the curable adhesive composition.